JPH1051895A - Speaker device - Google Patents

Abstract

(57) [Problem] To provide a plurality of coils as drive coils of an electromagnetically coupled speaker, connect each end of each coil and each input terminal by simple work and labor. Connection without error. SOLUTION: A magnetic circuit 20 having a gap 23 between a center pole section 12 and a plate 22 is constituted. A plurality of coils are fixed as the primary coil 1 at the tip of the center pole portion 12, and the secondary coil 2, which is fixed to the cone 32 and forms a short coil, is disposed in the gap 23.
An intermediate terminal 39 is provided at a position on the front side of the center pole yoke 11 between the outer peripheral surface of the center pole portion 12 and the inner peripheral surface of the magnet 21.
An input terminal 18 is provided on the rear side of the device 1. The winding start portion and the winding end portion of each coil of the primary coil 1 are connected to the intermediate terminal 39, and the intermediate terminal 39 is connected to the input terminal 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker device for sound reproduction.

[0002]

2. Description of the Related Art Various types of speakers for sound reproduction have been considered and put to practical use.

For example, a magnetic circuit having a gap between a center pole portion of a center pole yoke and a plate is formed by sandwiching a magnet between a center pole yoke and a plate, and a center pole is formed in the gap of the magnetic circuit. A primary coil, which is a driving coil, is fixed to a part or a plate, and a speaker unit in which a secondary coil constituting a short coil is arranged in a gap of a magnetic circuit by being fixed to a diaphragm so as to be opposed to the primary coil. It has been put to practical use as a coupled (electromagnetic induction type) speaker.

In this electromagnetically coupled speaker, a secondary current is induced in a secondary coil constituting a short coil by a signal current flowing through a primary coil which is a driving coil, and is interacted with a magnetic flux generated in a gap of a magnetic circuit. According to Fleming's left-hand rule, a driving force corresponding to the secondary current is generated in the secondary coil, and the diaphragm to which the secondary coil is fixed is displaced.

[0005] This electromagnetically coupled speaker has advantages in that the primary coil through which a signal current flows is fixed to a center pole or plate made of a magnetic material such as iron, so that it has excellent heat dissipation and can withstand a large input. If the secondary coil constituting the short coil is formed of a one-turn pipe or cylinder made of a non-magnetic conductive material, for example, aluminum, distortion can be reduced.

[0006]

In an electromagnetically coupled speaker, the winding start portion and the winding end portion of the primary coil, which is a driving coil, are generally provided with a coil lead wire formed on a center pole yoke. It is inserted into the opening and soldered to an input terminal provided on the rear surface of the center pole yoke to be connected to the input terminal.

FIG. 14 shows an example of a conventional electromagnetically coupled speaker, in which a recess 13 is formed around the tip of a center pole section 12 of a center pole yoke 11.
The primary coil 1 as a drive coil is fitted into the recess 13 and attached to the center pole portion 12.

[0008] An opening 15 is formed in the flange portion 14 of the center pole yoke 11 at a position close to the center pole portion 12.
The terminal plate 16 is attached. Then, a coil lead wire 17 made of, for example, a tinsel wire at a winding start portion and a winding end portion of the primary coil 1 is adhered to the peripheral surface of the center pole portion 12 and inserted into the opening 15, and the input terminal on the terminal plate 16 is provided. 18 by soldering.

A magnet 21 is bonded to the front surface of the flange portion 14 of the center pole yoke 11, and a plate 22 is bonded to the front surface of the magnet 21. A magnetic circuit 20 having an air gap 23 between the magnetic circuit 20 and the inner peripheral surface is formed.

The secondary coil 2 constituting a short coil is inserted into the gap 23 of the magnetic circuit 20. The secondary coil 2 is a one-turn pipe or cylinder made of a nonmagnetic conductive material, for example, aluminum.

An inner peripheral portion of a cone 32 having an outer peripheral portion with an edge 31, an inner peripheral portion of a center cap 33, and an inner peripheral portion of a damper 34 are attached to the secondary coil 2. Also,
A speaker frame 35 is attached to the plate 22, and the outer edge 31 of the cone 32 and the gasket 36 are attached to the speaker frame 35, and the outer periphery of the damper 34 is attached to the speaker frame 35.
Attached to.

The winding start and winding end of the primary coil 1 are of course connected to separate input terminals. And
The primary coil 1 is connected to the input terminal whose polarity is determined in advance.
After soldering the beginning and end of winding, or after completing the speaker,
Which input terminal is the end of winding, that is, the polarity of the input terminal is determined.

However, it is conceivable to provide a plurality of primary coils in order to directly drive the primary coils by digital audio signals. And in this case,
Connecting the winding start and end of each coil directly to the input terminal as described above causes the following inconvenience.

That is, in this case, for example, when it is determined in advance which input terminal is to which end of which coil, the center pole / yoke is made to correspond to it. After judging which end of each coil is which end of each coil on the front side of 11, this is replaced with the rear end of the center pole yoke 11.
It must be connected to the corresponding input terminal, and the connection between each end of each coil and each input terminal is not only time-consuming but also prone to connection errors, and coil pull-out. There are inconveniences such as the need to draw large lines.

Further, after connecting each end of each coil to an arbitrary input terminal, after completion of the speaker, any input terminal is for any end of any coil. When determining whether or not each of the coils has a corresponding relationship between each end and each of the input terminals, the relationship between the individual speakers becomes inconsistent, which hinders the connection between the speakers and their drive circuits. There are inconveniences such as coming.

Therefore, according to the present invention, when a plurality of coils are provided as drive coils of an electromagnetically coupled speaker, each end of each coil and each input terminal are connected by simple work and labor. The connection can be made in a predetermined correspondence without causing an error.

[0017]

According to the present invention, there is provided a magnetic circuit formed by a center pole yoke, a plate, and a magnet and having a gap between the center pole portion of the center pole yoke and the plate. A plurality of primary coils are fixed to a portion of the magnetic circuit in the vicinity of the gap, and a secondary coil that is fixed to a diaphragm and constitutes a short coil is disposed in the gap, and the center pole and An intermediate terminal is provided on the front side of the yoke, between the outer peripheral surface of the center pole portion and the inner peripheral surface of the magnet, or on the rear surface side of the center pole yoke. An input terminal is provided on the rear side of the primary coil, and a winding start portion and a winding end portion of each of the primary coils are connected to the intermediate terminal. It is continued, the intermediate terminal is connected to said input terminal, and things.

In the loudspeaker device of the present invention configured as described above, the winding start portion and the winding end portion of each primary coil are connected to the intermediate terminal, and the intermediate terminal is connected to the input terminal. The winding start and end portions of the primary coil and the respective input terminals are connected by a simple operation and labor without a connection error and in a predetermined correspondence.

[0019]

FIG. 1 shows an example of a speaker device according to the present invention, and FIG. 2 shows a center pole / yoke portion thereof. In the speaker unit 10 of this example, a concave portion is formed around the tip of the center pole portion 12 of the center pole yoke 11, and the primary coil 1 serving as a drive coil is fitted into the concave portion and attached to the center pole portion 12. Can be

As shown in FIG. 7 (A), the primary coil 1 is wound as an air-core coil, and is press-fitted into the above-mentioned recess to be attached to the center pole portion 12. Alternatively, as shown in FIG. 7B, the primary coil 1 is wound around a magnetic bobbin 12A having upper and lower flange portions 12c and 12e, and the magnetic bobbin 12A is press-fitted into the recess. Thereby, the primary coil 1 is attached to the center pole portion 12. Or, FIG.
As shown in (C), a flange portion 12g is formed at the tip of the center pole portion 12, and a concave portion 13 on the rear side thereof is formed.
The primary coil 1 is mounted on the center pole portion 12 by directly winding the primary coil 1.

In any case, the primary coil 1 is composed of a plurality of coils 1A, 1B,.
A coil lead wire 17a made of, for example, a tinsel wire is provided at a winding start portion and a winding end portion of 1B.

As shown in FIG. 1, an opening 15 is formed in the flange portion 14 of the center pole yoke 11 at a position slightly separated from the center pole portion 12, and at a position peripheral to the opening 15, A terminal plate 16 provided with input terminals 18 is attached to the rear surface of the flange portion 14.

The input terminals 18 are provided in a ring arrangement corresponding to the number of the winding start portions and the winding end portions of the coils 1A, 1B... , Which end is determined, and is distinguished by being marked or colored.

At the position between the opening 15 and the center pole portion 12, the intermediate terminal 3
The terminal plate 38 provided with 9 is attached. For example,
As shown in FIG. 3A, the coil lead 17as shown in FIG. 2 at the beginning of winding of the coil is connected as an intermediate terminal 39 on one insulating substrate 38A corresponding to one coil. A copper foil 39p to be attached and a copper foil 39m to be connected to the coil lead wire 17ae shown in FIG. 2 at the end of winding of the coil are attached, and the insulating substrate 38A is
As the terminal plate 38, the opening 15 on the front surface of the flange portion 14
The coil 1A,
1B... Are arranged in a ring and attached.

Alternatively, as shown in FIG. 3B, the copper foils 39p and 3p are placed on an annular insulating substrate 38B having a center hole 38b into which the center pole portion 12 is to be inserted.
9 m of intermediate terminals 39 are arranged and mounted in a ring shape by the number of coils 1A, 1B..., And the insulating substrate 38B serves as a terminal plate 38 as a center pole portion 12
And is attached to the front surface of the flange portion 14.

In each case, copper foil 39p and 39m
Is distinguished depending on its shape and position, whether it is for the winding start or the winding end. Further, for example, which coil is to be determined may be determined in advance, and a distinction may be made by marking or coloring the coil.

With the input terminal 18 and the intermediate terminal 39 attached to the center pole yoke 11 as described above, the primary coil 1, ie, the coils 1A, 1B,. ,
Next, it is determined which end of each coil 1A, 1B... Is which end of which coil, and the coil lead wire 17as at the winding start is connected to one end of the copper foil 39p. The coil lead wire 17ae at the end of winding
Is connected to one end of the copper foil 39m by soldering or the like.

At this time, the coil lead 17a is adhered to the outer peripheral surface of the center pole portion 12 with an adhesive applied around the coil lead wire 17a.
Through the coils 1A, 1B...

In this case, if it is determined in advance which coil each intermediate terminal 39 is to be connected to, the coil lead wire 17a of each coil 1A, 1B... Connected to the intermediate terminals, and if it is not determined in advance which coil each intermediate terminal 39 is for, the coil lead wire 17 of each coil 1A, 1B.
When a is connected to a certain intermediate terminal, the intermediate terminal is marked with a mark or color indicating which coil it is for.

Then, the coil leads 1 of all the coils
After connecting 7a to the intermediate terminal 39, one end of the coil lead wire 17b made of, for example, a tinsel wire passed through the opening 15 is soldered to the other end of the copper foil 39p or 39m, and the other end is soldered to the input terminal 18. By attaching, each intermediate terminal 39 is connected to the corresponding one of the input terminals 18.

By doing so, the winding start portion and the winding end portion of each of the coils 1A, 1B.
The respective input terminals 18 can be connected in a predetermined correspondence by a simple operation and effort without causing a connection error.

A magnet 21 is bonded to the front surface of the flange portion 14 of the center pole yoke 11, and a plate 22 is bonded to the front surface of the magnet 21. A magnetic circuit 20 having an air gap 23 between the magnetic circuit 20 and the inner peripheral surface is formed.

The secondary coil 2 constituting a short coil is inserted into the gap 23 of the magnetic circuit 20. The secondary coil 2 is a one-turn pipe or cylinder made of a non-magnetic conductive material, for example, aluminum, so that a bobbin around which the secondary coil 2 is wound can be omitted.

The secondary coil 2 is provided with an inner peripheral portion of a cone 32 having an edge 31 on the outer peripheral portion, a center cap 33, and an inner peripheral portion of a damper 34. Also,
A speaker frame 35 is attached to the plate 22, and the outer edge 31 of the cone 32 and the gasket 36 are attached to the speaker frame 35, and the outer periphery of the damper 34 is attached to the speaker frame 35.
Attached to.

The above-described speaker unit 10 can be assembled by the following method. First, as described above, the primary coil 1 is attached to the center pole portion 12 of the center pole yoke 11, and the coil lead wires 17as and 17ae at the winding start and end portions of the coils 1A, 1B. 39, and the intermediate terminal 39 is connected to the input terminal 18 by a coil lead wire 37b.

Next, an adhesive is applied to the front surface of the flange portion 14 of the center pole yoke 11 so that the magnet 2
Put 1 on. At this time, the inner diameter of the magnet 21 is set to be equal to the outer diameter of the magnet guide 14a provided on the center pole yoke 11. In addition, magnet 2
An adhesive is applied to the front surface of 1 and the plate 22 is placed.

The speaker frame 35 is attached to the plate 22 in advance by caulking or the like. Alternatively, after completion of the magnetic circuit 20, the plate 22
The speaker frame 35 may be attached to the speaker frame by means such as screws. The following method is a case where the speaker frame 35 is attached to the plate 22 in advance.

Next, a gap guide (not shown) is inserted into the center pole 12 so that the inner diameter of the plate 22 and the outer diameter of the center pole 12 are concentric.
After the adhesive has dried, place the gap guide in the center pole section 1
Remove from 2.

Next, a secondary coil 2 constituting a short coil and a coil spacer (not shown) are prepared.
A coil spacer is inserted into the inner diameter of the secondary coil 2, and the coil spacer is inserted into the center pole portion 12 so that the secondary coil 2 is located at a predetermined position in the gap 23 of the magnetic circuit 20.

Next, the outer periphery of the damper 34 is adhered to the speaker frame 35 and the inner periphery thereof is adhered to the secondary coil 2, respectively, and the cone 32 having an edge 31 on the outer periphery.
Attach the outer edge 31 and the gasket 36 to the speaker frame 35, and attach the inner periphery of the cone 32 to
Attach to secondary coil 2.

Next, after the adhesive is dried, the coil spacer is removed from the center pole portion 12, and the center cap 33 is bonded to the inner peripheral portion of the cone 32 or the tip of the secondary coil 2. After drying the adhesive, the magnet 21
Is completed, the assembly of the speaker unit 10 is completed.

FIG. 4 shows another example of the speaker device of the present invention, and FIG. 5 shows a center pole yoke portion thereof. In the speaker unit 10 of this example, an opening 15 is formed in the flange portion 14 of the center pole yoke 11 at a position close to the center pole portion 12, and at a position peripheral to the opening 15, the flange portion 14 is formed.
A terminal plate 16 provided with an input terminal 18 is attached to the rear surface of the terminal plate 16.

The input terminals 18 are provided in an annular arrangement corresponding to the number of the winding start portions and the winding end portions of the coils 1A, 1B... , Which end is determined, and is distinguished by being marked or colored.

In this example, the center pole portion 1
A terminal plate 38 provided with an intermediate terminal 39 is attached to the outer peripheral surface near the second opening 15. For example, as shown in FIG. 6A, one insulating substrate 3 corresponding to one coil
8A, a copper foil 39p to be connected to the coil lead wire 17as shown in FIG. 5 at the beginning of winding of the coil as an intermediate terminal 39, and a coil lead wire shown in FIG. 5 at the end of winding of the coil. 17ae is attached to the copper foil 39m to be connected, and the insulating substrate 38A is formed as a terminal plate 38 on the outer peripheral surface near the opening 15 of the center pole portion 12 by the number of coils 1A, 1B. It is arranged and attached to.

Alternatively, as shown in FIG. 6 (B), the above-mentioned copper foils 39p and 3p are formed on a flexible insulating substrate 38C.
9m of the intermediate terminals 39 are arranged and mounted in one direction by the number of the coils 1A, 1B,..., And the insulating substrate 38C is bent in a ring shape to form the terminal plate 38.
It is attached to the outer peripheral surface of the center pole portion 12 near the opening 15.

In each case, copper foil 39p or 39m
Is distinguished depending on its shape and position, whether it is for the winding start or the winding end. Further, for example, which coil is to be determined may be determined in advance, and a distinction may be made by marking or coloring the coil.

Then, with the input terminal 18 and the intermediate terminal 39 attached to the center pole yoke 11, the primary coil 1, ie, the coils 1A, 1B,... 1B... Of each coil are determined, and the coil lead wire 17as at the winding start is connected to one end of the copper foil 39p, and the coil at the winding end is determined. The lead wire 17ae is connected to one end of the copper foil 39m by soldering or the like.

At this time, the coil lead wire 17a is adhered to the outer peripheral surface of the center pole portion 12 with an adhesive applied around the coil lead wire 17a.
Through the coils 1A, 1B...

In this case, if it is determined in advance which coil each intermediate terminal 39 is to be connected to, the coil lead wire 17a of each coil 1A, 1B... Is determined. Connected to the intermediate terminals, and if it is not determined in advance which coil each intermediate terminal 39 is for, the coil lead wire 17 of each coil 1A, 1B.
When a is connected to a certain intermediate terminal, the intermediate terminal is marked with a mark or color indicating which coil it is for.

Then, the coil leads 1 of all the coils
7a is connected to the intermediate terminal 39, and one end of a coil lead wire 17b made of, for example, a tinsel wire, which passes through the opening 15, is soldered to the other end of the copper foil 39p or 39m, and the other end is soldered to the input terminal 18. By attaching, each intermediate terminal 39 is connected to the corresponding one of the input terminals 18.

By doing so, the winding start and end of each of the coils 1A, 1B.
The respective input terminals 18 can be connected in a predetermined correspondence by a simple operation and effort without causing a connection error.

The intermediate terminal can be attached to the center of the rear surface of the center pole yoke 11 where the input terminal 18 is attached. In this case, a through hole is formed at the axial center position of the center pole portion 12, and the coils 1A, 1B,.
Of the coil at the beginning and end of winding 17as
And 17ae may be led out through the through hole to the rear side of the center pole yoke 11 and connected to the intermediate terminal on the rear side.

Also in this case, similarly to the example shown in FIG. 1 or FIG. 4, the winding start and end portions of the respective coils 1A, 1B... The connection can be made in a predetermined correspondence without trouble of connection by trouble.

FIG. 8 shows an example of an audio reproduction system using the speaker device of the present invention, in which audio is reproduced by a digital audio signal from a digital audio output device.

The digital audio output device 210 is a CD player, a DAT (Digital Audio Tape Recorder), or the like.
Stereo audio signals composed of left and right audio signals, which are digitized into 16 bits at a sampling frequency of z or 48 kHz, are output as serial data alternately for each sample of left and right audio data.

The 16-bit digital audio signal of the serial data from the digital audio output device 210 is supplied to the serial / parallel converter 220, where the left and right digital audio signals are separated. Each of them is converted into parallel data, and the 16-bit left and right digital audio signals as the parallel data are converted into left and right speaker devices 100L, 100L.
00R.

In this example, the speaker devices 100L and 100R are respectively composed of a decoder 70 and a speaker driving circuit 4
0 and a speaker unit 10, and a decoder 70 generates a control signal, which will be described later, from a 16-bit digital audio signal converted into parallel data from the serial / parallel converter 220. The speaker unit 10 is supplied to the circuit 40 and driven by the speaker driving circuit 40.

The speaker unit 10 is the electromagnetically coupled speaker described above with reference to FIGS. 1 to 7, and in this example, the primary coil 1 as a drive coil is divided into fifteen coils 1A, 1B.
1N, 1P.

That is, in this example, the 16-bit digital audio signal from the serial / parallel converter 220 is linearly quantized with a 2's complement code as shown in FIG. Using the MSB (most significant bit) as a sign bit, as shown in FIGS. 9 and 10, the primary coil 1 is divided into fifteen coils 1A, 1B.
N, 1P, and the coil 1A is made to correspond to the LSB (least significant bit), for example, has two turns, and the coils 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1
J, 1K, 1L, 1M, 1N, 1P are converted to 15SB, 14
SB, 13SB, 12SB, 11SB, 10SB, 9S
B, 8SB, 7SB, 6SB, 5SB, 4SB, 3S
The number of turns is twice the number of turns of the coil corresponding to the next lower bit, such as 4 turns, 8 turns, 16 turns, etc., corresponding to B and 2SB.

FIG. 11 shows an example of a portion of the decoder 70 and the speaker drive circuit 40 shown in FIG. 8 in this case. The speaker drive circuit 40 includes 15 coils 1A to 1N and 1P of the primary coil 1. Correspondingly, there are 15 coil drive circuits 40A to 40N and 40P.

The respective coil drive circuits 40A
To 40N and 40P are constant current sources 41A to 41N and 41P.
And four FETs 5 as switching elements, respectively.
1 to 54 and the corresponding coils 1A to 1N and 1P are bridge-connected, and the FETs 51 and 53 are turned on.
When the FETs 52 and 54 are turned off, the current Ia of the corresponding constant current source flows in the corresponding coil in the plus direction, and when the FETs 51 and 53 are turned off and the FETs 52 and 54 are turned on, the corresponding constant current source Is caused to flow in the negative direction to the corresponding coil.

The currents of the constant current sources 41A to 41N and 41P are all set to the same current value as indicated by the current Ia. In the same coil drive circuit, FETs 51 to 54
Are turned on or off, no current flows through the corresponding coil.

The decoder 70 corresponds to the fifteen coils 1A to 1N and 1P of the primary coil 1, that is, the MSB of the digital audio signal from the serial / parallel converter 220.
15 control signal generation circuits 70A to 70N and 70P corresponding to the 15 bits except for the digital audio signal from the serial / parallel converter 220. MSB and
From the lower bits (LSB to 2SB) corresponding to the respective control signal generation circuits 70A to 70N and 70P, four control signals G1 to G4, which will be described later, are obtained, respectively.
The control signals G1 to G4 correspond to the FETs of the corresponding coil drive circuits 40A to 40N and 40P of the speaker drive circuit 40.
It is supplied to the gates 51-54.

When the MSB of the digital audio signal from the serial / parallel converter 220 is 0 and the corresponding lower bit is 1, the four control signals G1 to G4
1, G3 turns on the FETs 51 and 53, and the control signals G2 and G4 turn off the FETs 52 and 54. When the MSB is 0 and the corresponding lower bit is also 0, or when the MSB is 1, the corresponding When the lower bit to be set is also 1, the control signals G1 to G4 are at a level for turning off the FETs 51 to 54. When the MSB is 1 and the corresponding lower bit is 0, the control signals G1 and G3 are set to the FETs 51 and 54.
53 is a level to turn off, and control signals G2 and G4 are FETs
This is the level at which 52 and 54 are turned on.

Therefore, when the MSB is 0, the current Ia flows in the plus direction in the corresponding primary coil only when a certain lower bit is 1, and when the MSB is 1, the certain lower bit is 0. Only when is the current Ia flowing in the negative direction to the corresponding primary coil.

The driving force F of the vibration system of the electromagnetically coupled speaker is
The product of the secondary current i induced in the secondary coil, the density B of the magnetic flux generated in the air gap of the magnetic circuit, and the length L of the secondary coil in the air gap of the magnetic circuit is represented by F = BLi. Since the magnetic flux density B and the length L are constant, the driving force F of the vibration system is proportional to the secondary current i induced in the secondary coil. The secondary current i induced in the secondary coil is proportional to the product of the signal current flowing through the primary coil and the number of turns (impedance) of the primary coil.

In the example described above, the number of turns of each of the coils 1A to 1P of the primary coil 1 is set to a number of turns in proportion to the weight of each bit excluding the MSB of the digital audio signal from the serial / parallel converter 220. Thus, when the current Ia flows as a signal current through a certain primary coil,
In the secondary coil 2, a secondary current having a current value proportional to the bit weight corresponding to the primary coil in a direction corresponding to the MSB value of the digital audio signal from the serial / parallel converter 220 is induced.

Therefore, the cone 32 to which the secondary coil 2 is fixed has an amount proportional to the weight of the bit corresponding to the primary coil in a direction corresponding to the MSB value of the digital audio signal from the serial / parallel converter 220. Only displaced,
In the speaker unit 10, sound is faithfully reproduced according to the digital sound signal from the serial / parallel converter 220.

In general, an electromagnetically coupled speaker is excellent in heat dissipation, can withstand a large input, and can reduce distortion. However, an electromagnetically coupled speaker in which a secondary current is induced in a secondary coil by a signal current flowing through a primary coil. The coupling force is reduced in a low frequency range of several kHz to 1 kHz or less, and it is difficult to reproduce sound up to 20 Hz necessary for reproducing sound. Therefore, the electromagnetically coupled speaker is mainly used as a speaker for reproducing high-frequency sound.

However, the digital audio signal from the serial / parallel converter 220 shown in FIG. 8 or FIG.
Each coil 1A of the primary coil 1 is digitized at a sampling frequency of 4.1 kHz or 48 kHz.
.About.1P are driven by digital signals of the same sampling frequency, so that several kHz of the audio signal before digitization
Even low frequency components such as z to 1 kHz or less have high frequencies exceeding 20 kHz as signal currents flowing through the coils 1A to 1P of the primary coil 1.

Accordingly, the speaker unit 10 which is an electromagnetically coupled speaker enables reproduction in a low frequency range, thereby realizing a full-range speaker for reproducing low to high frequencies.

As with a general speaker, the vibration system of the speaker unit 10 is difficult to respond to high frequencies,
High frequency components exceeding Hz are hardly reproduced. Therefore, each of the coils 1A to 1P of the primary coil 1
Is driven by a digital signal having a sampling frequency of 44.1 kHz or 48 kHz, the sampling frequency component is hardly reproduced. Even if the sound is reproduced with a very small sound pressure, the sound exceeding 20 kHz can hardly be heard by the human ear, so that there is no trouble even when listening to music. Further, it is easy to intentionally form a mechanical filter having a stop band of 20 kHz or more and to incorporate the mechanical filter into the speaker unit 10.

Further, it is possible to realize a speaker device that reproduces sound directly by a digital sound signal without using a D / A converter and a power amplifier, that has a small distortion and a large maximum output.

The audio reproduction system of FIG. 8 integrates, for example, the serial-to-parallel converter 220 to the speaker drive circuit 40, connects it to the digital audio output device 210, and connects the speaker unit 10 thereto. Alternatively, the configuration from the serial / parallel converter 220 to the speaker unit 10 may be integrated and connected to the digital audio output device 210.

In the above example, the number of turns of each of the coils 1A to 1P constituting the primary coil 1 is set to a number of turns in proportion to the weight of each bit excluding the MSB of the digital audio signal from the serial / parallel converter 220. In this case, the difference in the weight of each bit of the digital audio signal is reproduced. However, the number of turns of each of the coils 1A to 1P is the same, and the constant current sources 41A to 41A of the corresponding coil drive circuits 40A to 40P. By changing the current value of 41P,
The difference in the weight of each bit of the digital audio signal from the serial / parallel converter 220 can be reproduced.

FIG. 12 shows an example of this case. The 15 coils 1A to 1N and 1P constituting the primary coil 1 all have the same number of turns, for example, 10 turns, and the coils 1A to 1N, Constant current sources 41A to 41N, 4 of coil drive circuits 40A to 40N, 40P corresponding to 1P
The 1P currents Ia to In and Ip are changed as described later. The rest is the same as the example of FIG.

As described above, the driving force F of the vibration system of the speaker unit 10 is proportional to the secondary current i induced in the secondary coil 2, and the secondary current i is the signal current flowing through the primary coil 1. And the number of turns (impedance) of the primary coil 1.

For this reason, in this example, although omitted in FIG. 12, as shown in FIGS. 9 and 10, the 15SB of the digital audio signal from the serial / parallel converter 220 is used.
The current Ib of the constant current source of the coil driving circuit corresponding to the coil 1B corresponding to LSB is the current Ia of the constant current source 41A of the coil driving circuit 40A corresponding to the coil 1A corresponding to the LSB.
Is twice as large as That is, Ib = 2Ia.

The currents Ic, Id, Ie of the constant current sources of the coil driving circuits corresponding to the coils 1SB, 1SB, 1E,... Corresponding to 14SB, 13SB, 12SB,.
b, Ic, Id...

Therefore, as in the example of FIG. 11, in the speaker unit 10, the cone 32 corresponds to the primary coil through which the signal current flows in the direction corresponding to the MSB value of the digital audio signal from the serial / parallel converter 220. The digital audio signal is shifted by an amount proportional to the weight of the corresponding bit, and the audio is reproduced faithfully to the digital audio signal from the serial / parallel converter 220.

Further, the difference in the weight of each bit of the digital audio signal can be reproduced by a combination of the difference in the number of turns of the plurality of primary coils and the difference in the current value of the plurality of constant current sources.

FIG. 13 shows an example in that case. However,
In this example, when the 16-bit digital audio signal from the serial / parallel converter 220 is a natural binary code,
Alternatively, the digital audio signal of the 2's complement code as shown in FIG.
Is converted to a natural binary code.

In this example, the primary coil 1 is composed of 16 coils 1A, 1B... 1N, 1P, 1Q, the coils 1A to 1D correspond to the block A, the coils 1E to 1H correspond to the block E, and the coils 1I to 1H. 1L is block I, coil 1
M, 1N, 1P, 1Q are divided into four blocks so as to constitute the block M. For example, the coils 1A, 1E, 1I, 1M each have 10 turns, and the coils 1B, 1F, 1J, 1N has 20 turns each, the coils 1C, 1G, 1K, 1P have 40 turns each, and the coils 1D, 1H, 1L, 1Q
Are 80 turns each.

The constant current sources 61A to 61D of the current Ia are connected to the coils 1A to 1D via switch circuits 62A to 62D, respectively.
Constant current sources 61E to 61H each having a current 16 times the current Ia with respect to E to 1H are connected to the switch circuit 62, respectively.
Are connected via a E～62H, the coil 1I～1L, constant current source 16 ² times the current of each current Ia 61
I~61L are connected respectively via the switching circuit 62I～62L, constant current source coils 1M, 1N, 1P, against 1Q, 16 ³ times the current in the respective current Ia 61
M, 61N, 61P, 61Q are connected via switch circuits 62M, 62N, 62P, 62Q, respectively, and switch circuits 62A, 62B-62N, 62P, 62Q
Is switched by the data of the corresponding bit of the digital audio signal from the serial / parallel converter 220.

As described above, the driving force F of the vibration system of the speaker unit 10 is proportional to the secondary current i induced in the secondary coil 2, and the secondary current i is the signal current flowing through the primary coil 1. And the number of turns (impedance) of the primary coil 1.

Therefore, in this example, when a certain bit of the digital audio signal from the serial / parallel converter 220 becomes 1, the switch circuits 62A to 62N,
When the corresponding ones of 62P and 62Q are turned on and the signal current flows through the corresponding ones of the primary coils 1A, 1N, 1P and 1Q, the ratio of the secondary current induced in the secondary coil 2 becomes serial. It becomes equal to the weight ratio of each bit of the digital audio signal from the parallel converter 220.

Accordingly, in the speaker unit 10, the cone 32 is shifted in one direction by an amount proportional to the weight of each bit of the digital audio signal from the serial / parallel converter 220, and the digital signal from the serial / parallel converter 220 is shifted. Sound is reproduced faithfully to the sound signal.

In this example, the ratio of the number of turns between the coils 1A, 1E, 1I, 1M having the minimum number of turns and the coils 1D, 1H, 1L, 1Q having the maximum number of turns is:
It is possible to significantly reduce and so 8, the ratio of the current value between the minimum current value and maximum current value 1:16 3 = ^1: it is possible to reduce and so 2 ^12.

In each of the above examples, when the digital audio signal for driving the primary coil 1 of the speaker unit 10 is linearly quantized and the primary coil 1 is composed of a plurality of coils, the plurality of coils are used. Number of turns, or each bit excluding MSB of digital audio signal, or MSB
In the case where the current value of the constant current source corresponding to each bit including is changed in geometric progression, when the digital audio signal driving the primary coil 1 is non-linearly quantized, Depending on the mode of quantization, when the primary coil 1 is composed of a plurality of coils, it corresponds to the number of turns of the plurality of coils, or each bit excluding the MSB of the digital audio signal, or each bit including the MSB. The current value of the constant current source may be changed.

[0090]

As described above, according to the present invention, when a plurality of coils are provided as drive coils for an electromagnetically coupled speaker, each end of each coil and each input terminal can be simply connected. The connection can be established in a predetermined correspondence without an error in the connection due to complicated work and labor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a speaker device according to the present invention.

FIG. 2 is a perspective view showing a center pole / yoke portion of the speaker device of FIG.

FIG. 3 is a diagram illustrating an example of an intermediate terminal of the speaker device of FIG. 1;

FIG. 4 is a sectional view showing another example of the speaker device of the present invention.

FIG. 5 is a perspective view showing a center pole / yoke portion of the speaker device of FIG. 4;

FIG. 6 is a diagram illustrating an example of an intermediate terminal of the speaker device of FIG. 4;

FIG. 7 is a diagram illustrating an example of a primary coil of the speaker device of FIG. 1 or FIG. 4;

FIG. 8 is a block diagram showing an example of a sound reproduction system using the speaker device of the present invention.

FIG. 9 is a diagram provided for describing an example of a digital audio signal.

FIG. 10 is a diagram showing an example of a coil configuration of the speaker device of the present invention.

FIG. 11 is a connection diagram illustrating an example of the speaker device of the present invention.

FIG. 12 is a connection diagram showing another example of the speaker device of the present invention.

FIG. 13 is a connection diagram showing still another example of the speaker device of the present invention.

FIG. 14 is a sectional view showing an example of a conventional speaker device.

[Explanation of symbols]

10 speaker unit, 1, 1A, 1B, 1C, 1
D, 1E, 1F, 1G, 1H, 1I, 1J, 1K, 1
L, 1M, 1N, 1P, 1Q: Primary coil, 2: Secondary coil, 11: Center pole and yoke, 12: Center pole part, 17a, 17b: Coil lead wire, 18: Input terminal, 20: Magnetic circuit, Reference numeral 21: magnet, 22: plate, 23: gap, 32: cone, 39: middle terminal, 4
0: speaker drive circuit, 40A to 40P: coil drive circuit, 41A to 41P, 61A to 61Q: constant current source

Claims (2)

[Claims] A magnetic circuit formed by a center pole yoke, a plate, and a magnet and having a gap between a center pole portion of the center pole yoke and the plate; In the vicinity, a plurality of primary coils are fixed, and a secondary coil that is fixed to a diaphragm and constitutes a short coil is disposed in the gap, and the center on the front side of the center pole yoke is provided. At a position between the outer peripheral surface of the pole portion and the inner peripheral surface of the magnet, or on the rear surface side of the center pole yoke,
An intermediate terminal is provided and the center pole
An input terminal is provided on a rear surface side of the yoke, a winding start portion and a winding end portion of each of the primary coils are connected to the intermediate terminal, and the intermediate terminal is connected to the input terminal. 2. A speaker unit comprising: a speaker unit; and a speaker drive circuit, wherein the speaker unit is formed by a center pole yoke, a plate, and a magnet, and is provided between a center pole portion of the center pole yoke and the plate. A plurality of primary coils are fixed to a portion of the magnetic circuit in the vicinity of the gap, and a secondary coil that is fixed to a diaphragm in the gap and constitutes a short coil Is disposed on the front side of the center pole yoke, at a position between the outer peripheral surface of the center pole portion and the inner peripheral surface of the magnet, or on the rear side of the center pole yoke,
An intermediate terminal is provided and the center pole
An input terminal is provided on a rear surface side of the yoke; a winding start portion and a winding end portion of each of the primary coils are connected to the intermediate terminal; the intermediate terminal is connected to the input terminal; A speaker device for driving the primary coil of the speaker unit by a digital audio signal.